This invention relates to apparatus and methods for applying a coating over a substrate and, more particularly, to apparatus and methods for blending and applying a coating material over a substrate by one or more applicators.
Automobile bodies are treated with multiple layers of coatings, for example primer, basecoat, and topcoat, that enhance the appearance of the automobile and also provide protection from corrosion and other environmental conditions that can deteriorate the coating appearance and the underlying car body. Currently, these coatings are applied to an automotive substrate at separate coating stations, with each station having multiple coating applicators connected to separate sources of pre-mixed coating materials. This procedure requires a great deal of floor space to accommodate each of the separate coating stations as well as the numerous applicators to apply the different coating materials onto the substrate.
In conventional automotive coating systems, the applicators are typically connected to a number of large, e.g., 200 gallon to 600 gallon (760 to 2280 liters), coating supply piping systems or xe2x80x9cloopsxe2x80x9d. Each loop supplies the applicators with a single, pre-mixed, color pigmented and fully effect-pigmented coating material. Switching blocks are used to selectively connect the applicators of a particular coating station to one of the coating loops to apply a desired coating material onto the substrate. Examples of conventional coating systems and switching blocks are described in U.S. Pat. Nos. 4,714,044; 4,532,148; 4,539,932; 4,902,352; 4,881,563; and 4,728,034, which are herein incorporated by reference in their entirety.
In these known systems, the number of coating materials or colors available for application must necessarily be limited due to the large storage and circulation requirements (760 to 2280 liters) for the coatings in the various coating supply loops. Due to this large storage requirement, it is not unusual for an automobile manufacturer to limit the available color selection for a particular automotive model to only six or seven colors. If one of these colors should prove unpopular with consumers, the manufacturer may be forced to discontinue the use of this color, resulting in a financial burden caused by the storage and/or disposal costs for the undesired color already on hand. Additionally, the pre-mixed coating materials in the coating loops are continuously agitated and/or circulated to prevent the coating components from settling. With time, this circulation can affect the perceived color of the coating material. For example, many automotive coating materials contain metallic flakes. The continuous circulation in the coating supply loops can bend or damage these metallic flakes, altering the perceived color characteristics or shading characteristics of the deposited coating.
As will be appreciated by one of ordinary skill in the automotive coating art, it would be advantageous to provide coating systems and/or methods that reduce the required number of coating stations and/or the number of coating applicators needed to apply one or more coatings over an automotive substrate. It would further be advantageous to provide coating methods and/or apparatus that can increase the colors available for an automaker without unduly increasing storage costs for the coating materials.
A coating system of the invention comprises a coating station, a conveyor configured to move a substrate to be coated through the coating station, at least one coating device located at the coating station, and a turntable located at the coating station and configured to move, e.g., turn and/or tilt and/or elevate, the substrate during the coating process.
Another coating system comprises a first coating station including at least one coating device having at least one movably mounted applicator. A turntable is movably mounted at the first coating station. A dehydration station is located downstream of the first coating station and can include an optional second movable turntable. A second coating station is located downstream of the dehydration station and includes at least one movably mounted applicator and a third movable turntable. A drying station is located downstream of the second coating station and can include an optional fourth movable turntable.
A coating apparatus of the invention comprises a first dynamic mixing system comprising a plurality of first coating components of differing color. At least one reservoir is in flow communication with the first dynamic mixing system. At least one applicator is in flow communication with the at least one reservoir.
Another coating apparatus comprises a first dynamic mixing system comprising a plurality of first coating components that are substantially free of effect pigments and a second dynamic mixing system comprising a plurality of second coating components comprising effect pigments. A first directional control device is connected to the first and second dynamic mixing systems. A plurality of reservoirs are connected to the first directional control device. A second directional control device is connected to the reservoirs. A plurality of applicators are connected to the second directional control device.
A method of applying a coating onto a substrate comprises the steps of providing a plurality of waterborne color components, dynamically blending selected color components to form a plurality of coating materials of selected color, directing the coating materials to separate reservoirs, and directing a coating material from one or more of the reservoirs over the substrate by a plurality of applicators.